Fundamental frequency

From AudioLexic

The fundamental tone, often referred to simply as the fundamental and abbreviated fo, is the lowest frequency in a harmonic series.

The fundamental frequency (also called a natural frequency) of a periodic signal is the inverse of the pitchperiod length. The pitch period is, in turn, the smallest repeating unit of a signal. One pitch period thus describes the periodic signal completely. The significance of defining the pitch period as the smallest repeating unit can be appreciated by noting that two or more concatenated pitch periods form a repeating pattern in the signal. However, the concatenated signal unit obviously contains redundant information.

A 'fundamental bass' is the root note, or lowest note or pitch in a chord or sonority when that chord is in root position or normal form.

In terms of a superposition of sinusoids (for example, fourier series), the fundamental frequency is the lowest frequency sinusoidal in the sum.